This invention relates in general to an energy management device adapted for attachment between a seat back and a seat track for dissipating energy of the seat back with respect to the lower seat frame in forward and rearward impacts in a vehicle seat assembly.
In an accident condition, large impact forces may be delivered to the occupant of the seat in both a rearward or frontal impact. In a rearward impact, the occupant is forced against the seat, and may experience a large energy pulse. Similarly, in a forward impact, in vehicle seats which incorporate the belt restraint system directly into the seat back, the occupant will engage the restraint system, and therefore may receive a large energy pulse from the seat which supports this restraint system.
To absorb the energy during a large energy pulse, several absorption assemblies have been developed. For example, commonly-assigned U.S. Pat. No. 5,722,722 to Massara discloses a vehicle seat energy absorber including a recliner/damper assembly which dampens energy of the seat back as it pivots with respect to the seat track in a high energy impact. The damper mechanism comprises a bi-directional damper that provides a different damping behavior in the forward and rearward directions. The recliner mechanism includes a clevis pin that is explosively released in a high energy impact to selectively disengage the recliner mechanism from the damper mechanism to allow the damper mechanism to dissipate energy of the seat back as it pivots with respect to the seat track.
In another example, commonly-assigned U.S. Pat. No. 5,826,937 to Massara discloses an energy absorbing seat assembly that includes a head restraint system incorporating a damper mechanism positioned between the upper end of the seat back and the heat restraint for energy management in a high energy impact. The damper mechanism is configured to dissipate head restraint energy in a rearward impact to cushion the load transfer between the occupant and the head restraint.
However, the above-mentioned damper mechanisms dissipate the energy pulse during impact by using a half-stroke of the damper, rather than in a reciprocating or oscillating stroke of the damper to provide increased management the energy dissipated by the damper. Further, the above-mentioned damper mechanism effectively dissipates energy only for only one impact event having a large energy pulse, rather than for a wide range of impact events having large and small energy pulses. Thus, it is desirable to provide a damped energy management device that can effectively dampen the energy pulse by using a reciprocating or oscillating stroke for a wide range of impact events having large and small energy pulses.
This invention relates to a vehicle seat assembly comprising a seat track, a seat back pivotally connected with respect to the seat track, and an oscillating damped energy management device secured between the seat back and the seat track. The device comprises a recliner arm secured to the seat back, a gear shaft operatively coupled to the recliner arm, a first damper crank mounted on the gear shaft, a first damper cylinder operatively coupled to the first damper crank by a first damper rod. The rotational movement of the first damper crank causes an oscillating movement of the first damper rod, thereby causing the first damper cylinder to dissipate energy during forward and rearward impacts of the vehicle seat assembly.
In another aspect of the invention, an oscillating damped energy management device is secured between a seat back and a seat track of a vehicle seat assembly. The device comprises a first damper crank mounted on a gear shaft, the gear shaft being coupled to the seat back of the vehicle seat assembly, a first damper cylinder, and a first damper rod coupling the first damper cylinder and the first damper crank. The rotational movement of the first damper crank causes an oscillating movement of the first damper rod, thereby causing the first damper cylinder to dissipate energy during forward and rearward impacts of the vehicle seat assembly.
In a method of dissipating energy during forward and rearward impacts of a vehicle seat assembly by using an oscillating damped energy management device secured between a seat back and a seat track of the vehicle seat assembly, the method comprises the steps of:
a) mounting a first damper mounted on a gear shaft, the gear shaft being coupled to the seat back of the vehicle seat assembly;
b) providing a first damper cylinder; and
c) coupling the first damper cylinder to the first damper crank by a first damper rod,
whereby a rotational movement of the first damper crank causes an oscillating movement of the first damper rod, thereby causing the first damper cylinder to dissipate energy during forward and rearward impacts of the vehicle seat assembly.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.